This invention relates to a method and system to dynamically configure signal protocols used in public switching telephone network processing devices.
Public Switching Telephone network (xe2x80x9cPSTNxe2x80x9d) devices such as Plain Old Telephone Switch (xe2x80x9cPOTSxe2x80x9d), Carrier Switches, Private Branch Exchange switches, Network Access Servers (xe2x80x9cNASxe2x80x9d), and the like are all interconnected using Time Division Multiplexed (xe2x80x9cTDMxe2x80x9d) connections to transmit data such as speech between them. Furthermore, these network devices require a means to communicate between the various endpoints to accurately manage the actual voice or data payload on each of the connections. This call management is achieved with the use of signaling to relay call information between the different endpoints. This signaling is in addition to the actual voice or data payload that is transferred over the telephone network. For example, this signaling may transfer the phone numbers used in the telephone network to set up the connection links within the network to interconnect two or more end user devices, such as phones, together. In other examples, this signaling is used to inform the other endpoint of resource availability.
Various signaling protocols and architectures are used to interconnect devices within the PSTN. Over the years, little has changed with respect to the actual voice or data payload transfer over a DSO timeslot on a TDM trunk. However, the signaling between the various PSTN devices has evolved substantially. Originally, the first digital signaling was designed to be in-band and share the DSO timeslot with the actual voice or data payload. These TDM trunks were known as Pulse Trunk Signaling (xe2x80x9cPTSxe2x80x9d) trunks. Various flavors of PTS trunks have evolved in different geographical markets to address national regulatory and market requirements. Years later, new signaling architectures evolved to address architectural problems with PTS trunks caused due to the fact that the signaling was still in-bank, such as blue-box fraud. Prime Rate Interface and Basic Rate Interface trunks evolved whereby a dedicated timeslot within a trunk was used for signaling; thus, not having to share a common medium with the voice and data payload such as PTS trunks. Newer signaling architectures such as Signaling System 7 (xe2x80x9cSS7xe2x80x9d) have further changed the PSTN architecture whereby the signaling is being done separately from the trunks transmitting the voice and data payloads, giving more connectivity and management functionality than previously possible at a network wide level. All the signaling formats are predominately standardized and do not deviate from the standard. Furthermore, flavors of all these trunk types coexist in the current PSTN architecture. Although PTS trunks are considered old technology, their low lease access rates make them very popular in many PSTN architectures. This invention will concentrate on a PTS trunk flavor used within PSTN known as Channel Associated Signaling (xe2x80x9cCASxe2x80x9d).
There exists a number of different CAS signaling types. However, each signaling type has a line or supervisory signaling component, and optionally an address component. The line or supervisory signaling initiate and terminate calls, and the address component which is for communicating the Dialed Number Identification Service (xe2x80x9cDNISxe2x80x9d) and Automatic Number Identification (xe2x80x9cANIxe2x80x9d). This invention will focus on the line or supervisory signaling.
In some equipment, the line signaling components are hard-coded within the software with knobs available on commonly customized parameters. However, there are still cases where the existing knobs do not provide the flexibility required and a development cycle is required to modify the line signaling state machine. To make things more complicated, the line signaling state machine has been implemented in different ways for different platforms in both international and national areas.
Hence, there exists a need for a configurable interface to CAS line signaling to customize or even write entirely new line signaling types in the field so that equipment manufacturers do not need to rewrite software for each platform.
An apparatus for configuring CAS line signaling using plain text strings includes at least one configurable CAS plain text line signal template having corresponding associated CAS signal parameters, a memory to store the configurable CAS plain text line signal template, a trunk controller to receive and transmit the CAS signal parameter, and a processor to match and interpose the configurable CAS plain text line signal template with the associated CAS parameters. The method for configuring CAS line signaling using plain text strings includes defining in a call processor at least one CAS plain text line signal template having corresponding signaling parameters, detecting the signaling parameters, selecting the CAS plain text line signal template using the signaling parameters to create a CAS protocol, and executing the CAS protocol.